Extracting a WAR File in Linux

Introduction

WAR (Web ARchive) files are a type of archive file used to package web applications into a single file. They are similar to Java ARchive (JAR) files and are typically used to deploy web applications in a Java environment. In this article, we will learn how to extract a WAR file on Linux using the command line.

A WAR file is essentially a ZIP file that contains all the files needed for a web application, including HTML, CSS, JavaScript, and Java files. Checking out a WAR file allows you to access the individual files it contains and make changes to the web application.

Prerequisites

Before you begin, make sure you have the following prerequisites −

• A Linux machine with command line or shell access.

• The “jar” command, which is part of the java-1.8.0-openjdk package. This package is usually installed by default on most Linux distributions. If it's not installed on your system, you can install it using your distribution's package manager. For example, on a CentOS system, you can install it using the following command −

$ sudo yum install java-1.8.0-openjdk

• The unzip command, which is part of the unzip package. This package is also usually installed by default on most Linux distributions. If it's not installed on your system, you can install it using your distribution's package manager. For example, on a CentOS system, you can install it using the following command −

$ sudo yum install unzip

Extract a WAR file using the jar command

The jar command is a utility that is part of the Java Development Kit (JDK) and is used to manipulate Java Archive (JAR) files. It can also be used to extract WAR files, as they are simply a variant of JAR files.

To extract a WAR file using the jar command, follow these steps −

• Open a terminal window and navigate to the directory where the WAR file is located. You can use the “cd” command to change to the desired directory. For instance −

$ cd /path/to/file.war

• Extract the WAR file using the “xf” or “xvf” option of the jar command, as shown below −

$ jar xf mywebapp.war

• This will extract the contents of the WAR file into a directory with the same name as the WAR file, without the “.war” extension. For example, if your WAR file is named “mywebapp.war”, the extracted files will be placed in a directory named mywebapp.

• To extract the WAR file to a specific directory, use the C option of the jar command, followed by the directory path, as shown below −

$ jar xf mywebapp.war -C /path/to/extraction/directory

This will extract the contents of the

WAR

file to the specified folder or directory.

Extract a WAR file using the unzip command

The unzip command is a utility used to extract files from ZIP archives. It can also be used to extract WAR files, as they are simply ZIP files with a different file extension.

To extract WAR file using the unzip command, follow these steps −

• Open a terminal window and navigate to the directory where the WAR file is located. You can use the “cd” command to change to the desired directory. For instance −

$ cd /path/to/file.war

• Extract the WAR file using the unzip command, as shown below −

$ unzip mywebapp.war

• This will extract the contents of the WAR file into a directory with the same name as the WAR file, without the .war extension. For example, if your WAR file is named mywebapp.war, the extracted files will be placed in a directory named mywebapp.

• To extract the WAR file to a specific directory, use the -d option of the unzip command, followed by the directory path, as shown below −

$ unzip mywebapp.war -d /path/to/extraction/directory

• This will extract the contents of the WAR file into the specified directory.

Compare jar and unzip to extract WAR files

Now that we have learned how to extract WAR files using the jar and unzip commands, let's compare the two methods to see which is more suitable for extracting WAR files.

• Ease of use − The jar and unzip commands are easy to use and have a simple syntax. However, the unzip command is perhaps a little easier to use, as it doesn't require any additional options to unzip WAR files.

• Compatibility − The jar command is part of the JDK and is therefore compatible with all Java-based WAR files. On the other hand, the unzip command is a general purpose utility which can extract any ZIP file including WAR files.

• Performance − The jar command is optimized for working with JAR files and may be faster at extracting WAR files than the unzip command. However, the performance difference is likely to be negligible for most use cases.

In general, the jar and unzip commands are effective tools for extracting WAR files on Linux. You may prefer the jar command if you are working with Java-based WAR files and want to use a tool designed specifically for manipulating JAR files. On the other hand, the unzip command is a more general purpose tool which can extract any ZIP file including WAR files.

Conclusion

In this article, we learned how to extract a WAR file on Linux using the jar and unzip commands. Both commands can be used to extract WAR files, although the jar command may be preferred for extracting Java-based WAR files. By following the steps outlined in this article, you should be able to extract WAR files easily to your Linux machine.

As a final note, keep in mind that WAR files are typically used to deploy web applications and can contain sensitive information such as database credentials and configuration files. Therefore, it is important to handle them with care and remove them in a safe place.